Thursday, January 24, 2008
The great white shark, Carcharodon carcharias, also known as white pointer, white shark, or white death, is an exceptionally large lamniform shark found in coastal surface waters in all major oceans. Reaching lengths of about 6 m (20 ft) and weighing up to 2,250 kg (5,000 lb), the great white shark is the world's largest known predatory fish. It is the only surviving species
Females average 3.65m and males 2.85m, but the largest specimen recorded was 6.10m.
Great hammerheads are a dark olive colour with a pale underside. They have a hammer-shaped head, with eyes positioned at the end of each extension. Hammerheads have triangular, serrated teeth. The dorsal fin (on the back) is very large and pointed.
Great hammerheads inhabit shallow reefs and are found at moderate depths offshore in all tropical waters worldwide. They can sometimes be found in water less than 1m deep.
Great hammerheads are solitary, unlike scalloped hammerheads, and feed on other small sharks, rays (including sting rays), squid and bony fish. They are considered to be dangerous and attacks on humans have been documented.
Females give birth to 20-40 live pups which are about 70cm long at birth.
Great hammerheads are not considered to be endangered although they are hunted for sport and for their skin, which is used as leather.
The grey reef shark, Carcharhinus amblyrhynchos, is one of the most common sharks in Indo-Pacific waters, from the Red Sea to Easter Island. It is found at depths down to about 250 m in lagoons and close to islands and coral reefs.
As its name suggests, the shark is grey overall, with a white underside. The tips of most fins, except the first dorsal fin, are darker, and the trailing edge of the caudal fin has a prominent black margin. Some individuals have a white pattern on the leading edge of the dorsal fin. It has been recorded at up to 2.55 m. The blacktip reef shark looks similar, and is also common, but it is distinguished by a black tip on the first dorsal fin.
The goblin shark, Mitsukurina owstoni, is a deep-sea shark, the sole living species in the family Mitsukurinidae. The most distinctive characteristic of the goblin shark is the unorthodox shape of its head. It has a long, trowel-shaped, beak-like rostrum or snout, much longer than other sharks' snouts. Some other distinguishing characteristics of the shark are the color of its body, which is mostly pink, and its long, protrusible jaws. When the jaws are retracted, the shark resembles a pink grey nurse shark (Carcharias taurus) with an unusually long nose.
Mitsukurina owstoni is found in the deep ocean, far below where the sun's light can reach at depths greater than 200 meters. They can be found throughout the world, from Australia in the Pacific Ocean to the Gulf of Mexico in the Atlantic Ocean. They are best known from the waters around Japan, where the species was first discovered by modern science.
Goblin sharks feed on a variety of organisms that live in the deep waters they call their home. Among some of their known meals are deep-sea squid, crabs and deep-sea fishes. Very little is known about the species' life history and reproductive habits, as encounters with them have been relatively rare. As seemingly rare as they are however, there seems to be no real threat to their populations and so they are not